Field of the Invention
The present invention relates to an image processing apparatus, a method of controlling the image processing apparatus, and a storage medium.
Description of the Related Art
Typically, in copy processing in image processing apparatuses, various kinds of image processing are performed in order to accurately reproduce an original that has been read by a scanner. However, a more favorable image is obtained if show-through, which is an image on a back side of an original that appears on a front side, is not accurately reproduced. If paper itself is not white, as in the case of a newspaper, a more favorable image is obtained if the paper color is not accurately reproduced. Thus, a scanned image includes unnecessary information (hereinafter, background image). There is a function called under-color removal, which is a representative function for removing this background image. In this under-color removal, a signal value of each color that is a predetermined signal value or greater is converted into white, using a 1D-LUT (one dimensional look-up table). Thus, converting a signal value into white so as to not reproduce a pixel having this signal value will be hereinafter expressed as background removal. Meanwhile, if under-color removal is enhanced, highlights on an image are also removed, and therefore, Japanese Patent Laid-Open No. 2008-5317 proposes an image processing technique for determining a highlight region in an image and moderating under-color removal for this highlight region.
However, with the above technique, determination information regarding a color highlight region is essential for reproducing color highlights, and the 1D-LUT for under-color removal needs to be switched for one image in accordance with the determination.